Jae-Myung Cho is one of the most prideful and arrogant school/clan heads of the Murim and alliance. Despite having the responsibility of heading his school and maintaining the peace of the Murim, he is more concerned over avenging the loss of his pride and eye. Due to his excessive pride, he can't recognize his own faults as he failed to realize that the loss of his eye came from angering Goomoonryong after he mocked Un-Wol upon his death. His brash and brutish nature makes him unable to foresee any traps his opponents may lay out for him due to his unstable and quick temper which resulted in the loss of his last eye. Also he's extremely stubborn as despite how his attacks couldn't land any hits on Goomoonryong, he still refuses to ask for help because of his selfish desire to avenge his humiliation which eventually resulted in his death.

After Goomoonryong won the Shinmujengpe, the alliance masters couldn't accept the results and decided to confront Un-Wol. Un-Wol had broken their agreement by going outside his cave and raising a disciple who also insulted the entire Murim. The Iron Fist Munju attacks Goomoonryong, angry because a seat was stolen from his school, but he is quickly thrown aside by Un-Wol. When Un-Wol decides to sacrifice himself for his disciple, the Iron Fist Munju starts to mock him and almost defaces his corpse, angering Goomoonryong and causing him to destroy his right eye.

He first appears with the other leading masters of the Alliance as they discuss their inability to capture Shi-Woon. He then watches a tape recording of Goomoonryong's appearance at the Alliance headquarters and becomes easily provoked by Goomoonryong's mockery. Enraged, he decides to go outside in hopes of finding Goomoonryong.

Luckily for him, Goomoonryong was waiting for him. The Iron Fist Munju refusesed to alert the other Alliance leaders and decideied to battle him alone. Goomoonryong easily evadaved his attacks and as their battle went on, the building around them begun to collapse. Before he could escape, Goomoonryong pushed him back and destroyed his remaining left eye with his knee. Though the Iron Fist Munju got back up from the attack, Jae-Myung would later be found dead, with Goomoonryong leaving his corpse plastered on the side of a building. After seeing his corpse, the other Alliance masters decide to go after Goomoonryong before he reacheed the Koa Business Tower. The Alliance also decided not to inform the Iron Fist School of his death. However, after Goomoonryong informed the whole Alliance of the Iron Fist Munju's death via radio, the Iron Fist School members gathered in the Koa Business Tower to avenge his death.

Real Master Martial Artist (Iron Fist Style): As the munju of the Iron Fist School and an elder of the Martial Arts Alliance Jae-Myung is undoubtedly a master in martial arts where he was able to fight against Chun-Woo Han. Though he was unable to land a hit on the former he was able withstand Goomoonryong's attacks that the latter resorted to luring the munju into a trap before getting serious.

Iron Body Technique (Cheol-Dong-Gong): When using this technique the body becomes as "hard as forged steel." When Iron Fist Munju uses this technique he is able to punch through reinforced concrete and is able to deflect and flip a moving car. Its weakness: Hardening the body also slows its movement and although the users body is hard as steel, the eyes are not, to which Goomoonryong has demonstrated twice.[1] The technique is so strong that a large portion of building falling on him did not injure him. When this technique is activied the skin color will change in color from white to a darker color.[2]